//4.
#include<stdio.h>
int main()
{
	int year,mouth;
	printf("输入年份和月份：");
	scanf("%d%d",&year,&mouth);
		switch(mouth)
		{
			case 1:
			case 3:
			case 5:
			case 7:
			case 8:
			case 10:
			case 12:
				printf("该月有31天\n");
				break;
			case 2:
				if(( year % 4 == 0 && year % 100 != 0) || year % 400 == 0)
					printf("该月有28天\n");
				else
					printf("该月有29天\n");
				break;
			case 4:
			case 6:
			case 9:
			case 11:
				printf("该月有30天\n");
				break;
		}
	return 0;
}
